Stir the caramel topping and cinnamon together in a bowl. Toss in the apples, mixing until evenly coated. Spread apple mixture into an 20cm square baking dish.
Mix flour and brown sugar into the same bowl used to mix the apples. Cut in the butter with a knife or pastry blender until the mixture resembles coarse crumbs. Stir in the oats then crumble over the apples.
Bake in the preheated oven until the apples are tender and the topping is golden brown, 45 to 50 minutes.